Figure 1.
Map of sample locations in Canada and Alaska, U.S.A.
Figure 2.
Percentage of specimens, families, genera, species, additional infraspecific taxa, and unnamed hybrids in the data set from which rbcL and matK barcodes were recovered.
Numbers in parentheses are the total number of individuals (specimens, unnamed hybrids) and taxa (families, genera, species, additional infraspecific taxa) in each category in the data set.
Figure 3.
Relationship between herbarium specimen age and sequence recovery (%) for rbcL and matK.
Material was sampled from 1169 herbarium specimens collected between 1950–2010. These were divided into seven age classes and a Spearman rank correlation was used to test for a relationship between age class and percent recovery of rbcL (Spearman's rho 0.306, p = 0.50079) and matK (Spearman's rho 0.893, p = 0.012302). The matK analysis excluded Dryopteridaceae, Equisetaceae, Juncaceae, Polypodiaceae, and Lycopodiaceae, which failed for all samples for this marker due to primer mismatch. Numbers in parentheses are the total number of herbarium specimens sampled from each age class for rbcL and matK, respectively.
Figure 4.
Frequency distribution of infraspecific and congeneric interspecific genetic divergences of rbcL and matK.
Numbers in parentheses are the total number of comparisons for each category. Divergences were calculated using uncorrected p-distances.
Figure 5.
Resolution (%) of genera, species, and additional infraspecific taxa for rbcL, matK, and rbcL + matK in neighbour joining trees and BLAST searches.
Neighbour joining trees were generated from single-family alignments using uncorrected p-distances. Numbers in parentheses are the numbers of genera or species sampled in each data set. BLAST searches were not conducted for the combined rbcL + matK data.
Figure 6.
Species resolution (%) per family for rbcL, matK, and rbcL + matK.
Numbers in parentheses refer to the numbers of species for which barcode data were recovered for rbcL, matK, and rbcL + matK, respectively. Families with a single genus and species sampled are excluded. Dashes (-) indicate that no sequences were recovered.
Figure 7.
Species resolution (%) in ten genera with the greatest number of species sampled.
Numbers in parentheses refer to the number of species sampled for rbcL, matK, and rbcL + matK, respectively.
Figure 8.
Scatterplots of the number of species sampled in each genus against the percentage of species resolved in each genus with rbcL, matK, and rbcL + matK.
A. rbcL-175 genera (Pearson correlation coefficient r = 0.4180, n = 175, P < 0.0001), R2 = 0.1747. B. matK-159 genera (Pearson correlation coefficient r = 0.3685, n = 159, P < 0.0001), R2 = 0.1358. C. rbcL + matK-153 genera (Pearson correlation coefficient r = 0.3636, n = 153, P < 0.0001), R2 = 0.1322. Species resolution was scored in neighbour joining trees generated from uncorrected p-distances calculated from single-family alignments.